Sound-propagating diaphragm



Dec. 30, 1930. M. R. HUTCHISON I 1,786,949

"SOUND PROPAGATING DIAPHRAGM Filed May 2. 1928 IN VEN TOR.

Z BY 'ATTORNEYJ,

Patented Dec. 30, 1930 UNITED STATES PATENT OFFICEV MILLER REESEHUTGHISON, OF LLEWELYN PARK, WEST ORANGE, NEW JERSEY, AS

SIGNOR TO PREMIER LABORATORY COMPANY, A CORPORATION OF DELAWARESOUND-PROPAGATING DIAPHRAGM Application filed May 2, 1928. Serial No.274,528.

vide a sound propagating diaphragm one portion of which will vibrate toproduce sound waves of the upper portion of the musical register whileanother portion of the ,diaphragm vibrates to produce sound waves of thelower portion of the musical register.

One feature of the invention relates to the provision of connectingmeans between two portions of a sound propagating diaphragm wherebyvibrations of one portion of the diaphragm will produce vibration of adifferentcharacteristic in the other portion of the diaphragm.

Another feature of the invention relates to the provision of aconnecting means between portions of a sound propagating diaphragmwhereby sound waves of unlike characteristics propagated simultaneouslyfrom the different portions of the sound propagating diaphragm will notcause interference with their vibrations.

Other objects and features will appear from the following description inconnection with the accompanying drawings in which Figure 1 is a sideelevation of the present invention with a portion broken away.

Figure 2 is a front elevation of the sound propagatingdiaphragmembodying the present invention.

Like reference characters'denote like parts in the several figures ofthe drawing.

In the following description and claim, parts characteristic featuresand functions will be identified by specific means for convenience ofexpression, but they are intended to be as generic in their applicationto similar parts or equivalent construction as the art will permit.

Referring to the drawings for supporting a sound propagating diaphragm abase 10 is provided to which is securelyattached a supporting rim 11supporting a sound propagating diaphragm. An electromagnetic unit 12 isprovided, for actuating the diaphragm, supported by a cross member18secured to the rim 11. The electromagnetic unit 12 includes anactuatingarm 14ione end of which is secured to the sound propagatingdiaphragm for actuating the diaphragm in response to electrical wavesimparted to the electromagnetic unit 12.

For controlling the electromagnetic unit 12 in accordance with a signalwave, there 1s provided an energy responsive device 20, shown in theform of anantenna positioned to intercept radiant energy or so-calledHertzian waves. It is understood that such waves may be emittedfrom aradio broadcast station of conventional type, but as the emission ofsuch energy forms no partof the present invention, it is thought that adetailed description thereof may be omitted herein. .The emitted energypreferably takes the form of a carrier wave of high frequency modulatedin accordance with a signal current, the signal current corresponding inwave form to sound waves. The antenna 20 at the receiving station isoperatively connected to a tuner 21, a ground or counterpoise 22being-provi ded therefor. The tuner 21 may be variably adjusted so as totune the circuits 20, 22 to the frequency of the carrier wave which itis desired to receive and a connection comprising a pair of wires2323;extends from the tuner 21 to a detector-24 for impressing thereonelectrical waves of this predetermined frequency. The detector 24 may beof any usual form for detecting high frequency energyand producingtherefrom rectified or detected waves of signal frequency. 3 Thesesignal waves are transmitted over a pair of conductors 25 extending tothe input of an amplifier 26 whereby the signal energy is amplified to adesired degree. A pair of conductors 27 forms an operative connectionfrom the output of the amplifier 26 to the electromagnetic unit 1.2.Thus undulatory current of signal frequency is impressed upon theelectromagnetic unit 12 under control of received radiant energy.

For producing sound waves of both upper and lower portions of themusical register, a sound propagating diaphragm 30 is providedcomprising a cone formed from fibrous material such as paper or thelike, supported by the supporting rim 11, its apex being; operativelyconnected to the actuating arm 14:. A plurality of apertures 31 areprovided dividing the cone 30 into a central cone 32 and a surroundingtruncated cone 33. The apertures 31 are preferably arranged closelyadjacent forming a circle of apertures of a radius approximately onefourth the radius of the cone, the distance of spacing beingapproximately equal to the diameter of the apertures. These aperturesefiect the damping of the vibrations passing from the cone 32 to thetruncated cone 33.

In the operation of the device waves of the desired frequency areselected detected and amplified by the energy responsive device 20 andare supplied to the electromagnetic unit 12 which causes oscillation ofthe actuating rod 14 or if desired rod 14 may be oscillated by a stylusoperating on a phonographic record. Oscillations of the actuating rod 14are imparted to the cone 30 through the connecting of rod 14 to the apexof the cone 32, which because of its so small circumference and directattachment to the actuating arm 14 will be caused to vibrate at highfrequency producing sound waves of the upper portion of the musicalregister. Vibrations of the central cone 32 are imparted to thetruncated cone 33 through the material between the apertures 31 in theface of the cone. Thus the vibration of the truncated cone 33 will besimilar to but of a lower frequency and of greater length than thevibration of the central cone 32, propagating sound waves of the lowerportion of the musical register.

Thus it may be seen that the invention provides a sound propagating coneor diaphragm which will be small in size and light in weight, easy tomanufacture and which will be adapted for the simultaneous propagationof sound waves of boththe upper and lower portions of the musicalregister.

The invention upon which this application is based is broader than thespecific embodiments shown and described for the purpose of illustratingat least some of the ways in which it may be employed. The scope of theinvention is therefore to be understood as not being limited by thepresent specific descrip-

